Browsing by Author "Bhim Bali Prasad"

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A Critical Review on Clinical Application of Separation Techniques for Selective Recognition of Uracil and 5-Fluorouracil
(Springer India, 2016) Khushaboo Pandey; Rama Shankar Dubey; Bhim Bali Prasad
The most important objectives that are frequently found in bio-analytical chemistry involve applying tools to relevant medical/biological problems and refining these applications. Developing a reliable sample preparation step, for the medical and biological fields is another primary objective in analytical chemistry, in order to extract and isolate the analytes of interest from complex biological matrices. Since, main inborn errors of metabolism (IEM) diagnosable through uracil analysis and the therapeutic monitoring of toxic 5-fluoruracil (an important anti-cancerous drug) in dihydropyrimidine dehydrogenase deficient patients, require an ultra-sensitive, reproducible, selective, and accurate analytical techniques for their measurements. Therefore, keeping in view, the diagnostic value of uracil and 5-fluoruracil measurements, this article refines several analytical techniques involved in selective recognition and quantification of uracil and 5-fluoruracil from biological and pharmaceutical samples. The prospective study revealed that implementation of molecularly imprinted polymer as a solid-phase material for sample preparation and preconcentration of uracil and 5-fluoruracil had proven to be effective as it could obviates problems related to tedious separation techniques, owing to protein binding and drastic interferences, from the complex matrices in real samples such as blood plasma, serum samples. © 2015, Association of Clinical Biochemists of India.
A dual-ion imprinted polymer embedded in sol-gel matrix for the ultra trace simultaneous analysis of cadmium and copper
(Elsevier B.V., 2014) Bhim Bali Prasad; Darshika Jauhari; Archana Verma
In simultaneous determination of group of elements, there are inter-metallic interactions which result in a non-linear relationship between the peak current and ionic concentration for each of the element, at bare (unmodified) electrode. To resolve this problem, we have resorted, for the first time, to develop a modified pencil graphite electrode using a typical ion imprinted polymer network (dual-ion imprinted polymer embedded in sol-gel matrix (inorganic-organic hybrid nano-material)) for the simultaneous analysis of a binary mixture of Cd(II) and Cu(II) ions, without any complication of inter-metallic interactions and competitive bindings, in real samples. The adequate resolution of differential pulse anodic stripping voltammetry peaks by 725 mV (cf, 615 mV with unmodified electrode), without any cross-reactivity and the stringent detection limits as low as, 0.050 and 0.034 ng mL-1 (S/N=3) for Cd(II) and Cu(II) ions, respectively by the proposed sensor can be considered useful for the primitive diagnosis of several chronic diseases in clinical settings. © 2013 Elsevier B.V.
A dual-template biomimetic molecularly imprinted dendrimer-based piezoelectric sensor for ultratrace analysis of organochlorine pesticides
(Elsevier B.V., 2015) Bhim Bali Prasad; Darshika Jauhari
A double-template imprinted biomimetic dendritic nano-fibers based piezoelectric sensor was developed for the analysis of dichlorodiphenyltrichloroethane and hexachorobenzene prevalent together as organo-chlorinated pesticide residues in real samples, without any cross reactivity and false positives. For this, the immobilization of 2,5-thiophene dicarbonyl dichloride molecules was initially carried out on the surface of gold quartz crystal via Au-S links. Latter, these molecules were covalently attached to dendron molecules (monomer) followed by the free-radical polymerization at 65 °C, in the presence of both target analytes, cross-linker and initiator, leading to the development of self-assembled molecularly imprinted dendrimer nano-fibers on the gold surface. The method of analysis necessarily involved a typical 'saturation approach' in this work. Accordingly, one of the molecular cavities was completely saturated with an authentic amount of the respective analyte, whereas the cavity specific for other analyte was exposed to rebinding resulting in the frequency change in accordance with the mass of the analyte in question. Detection limits of dichlorodiphenyltrichloroethane and hexachorobenzene were realized as low as 0.75 and 0.69 ng mL-1 (S/N = 3), and linearity observed in the concentration ranges 5.0-150.0 and 5.0-75.0 ng mL-1, respectively. © 2014 Elsevier B.V. All rights reserved.
A dual-template imprinted polymer-modified carbon ceramic electrode for ultra trace simultaneous analysis of ascorbic acid and dopamine
(2013) Bhim Bali Prasad; Darshika Jauhari; Mahavir Prasad Tiwari
A dual-template imprinted polymer film containing dispersed multiwalled carbon nanotubes was exploited in the fabrication of a typical, reproducible, and rugged carbon ceramic electrode, adopting "surface grafting from" approach for the growth of a nanometer thin coating on its surface. For this, chloro groups were first introduced at the exterior surface of silica-carbon composite electrode through sol-gel modification using (3-chloropropyl)-trimethoxysilane, followed by an iniferter (sodium diethyl dithiocarbamate) initiated photopolymerization of functional monomer (2,4,6-trisacrylamido-1,3,5-triazine), mixed templates (ascorbic acid and dopamine), and cross-linker (ethylene glycol dimethacrylate), in the presence of multiwalled carbon nanotubes. The modified sensor was validated for the simultaneous analysis of ascorbic acid and dopamine in aqueous, blood serum, cerebrospinal fluid, and pharmaceutical samples, using differential pulse anodic stripping voltammetric technique. The oxidation peak potentials for both analytes were found to be well apart approximately by 300mV, which was large enough to allow selective and sensitive analysis of one in the presence of other, without any cross reactivity, interferences and false-positives. The detection limits realized by the proposed sensor, under optimized conditions, were found to be as low as 2.24ngmL-1 for ascorbic acid and 0.21ngmL-1 for dopamine (S/N=3). Such stringent limits could be considered suitable for the primitive diagnosis of several chronic diseases, in clinical settings. © 2013 Elsevier B.V.
A new micro-contact imprinted l-cysteine sensor based on sol-gel decorated graphite/multiwalled carbon nanotubes/gold nanoparticles composite modified sandpaper electrode
(Elsevier, 2015) Bhim Bali Prasad; Ragini Singh
A new ultrasensing sandpaper electrode was fabricated using micro-contact imprinting technique for the detection of several diseases manifested at acute level depletion of l-cysteine. The concerted effect of molecularly imprinted polymer@graphite/multiwalled carbon nanotubes/gold nanoparticles/sol-gel composite led to the growth of a nanometer thin film coating on the surface of sandpaper electrode. Herein, the redox electron relay was channelized in between imprinted nanocomposite and aluminum stripe attached at the modified surface. Determination of the analyte (l-cysteine) could simply be performed by measuring differential pulse anodic stripping voltammetric signal of potassium ferricyanide used as an external probe. The limits of detection [0.26-0.30 ng mL-1 (3σRSD ≤ 2.5%)] obtained were free from any cross-reactivity and false-positive complications in aqueous, blood serum, and pharmaceutical samples. The proposed sensor can be used as a practical sensor for monitoring cysteine deficiency, particularly with HIV-infected patients. © 2015 Published by Elsevier B.V.
A novel electrocatalytic nanocomposite of reduced graphene oxide/silver nanocube hybrid decorated imprinted polymer for ultra-trace sensing of temozolomide
(Royal Society of Chemistry, 2018) Purnendu Kumar Pathak; Anil Kumar; Bhim Bali Prasad
A new nanocomposite of reduced graphene oxide/silver nanocube hybrid decorated molecularly imprinted polymer at the surface of a screen-printed carbon electrode was developed for the electroanalysis of an anticancerous drug, temozolomide, at the ultra-trace level. For this, a hybrid of reduced graphene oxide/silver nanocubes was successfully obtained through the simultaneous reduction of Ag+ and graphene oxide via simple one-pot green synthesis. Among the various shapes of nanomaterials used in imprinted polymer synthesis, silver nanocubes, as evident from SEM, TEM and, X-ray diffraction methods, have been found to render high surface to volume ratios and a higher electrocatalytic activity. Herein, the synergistic electrocatalytic effect of reduced graphene oxide and silver nanocubes was utilized for decreasing the analyte oxidation overpotential, without any interfacial barrier in between the imprinted film and the electrode surface, owing to the porous texture of the coating. Consequently, approximately 3-fold differential pulse anodic stripping current and ∼5-fold electron transfer rate kinetics were obtained on the reduced graphene oxide/silver nanocube hybrid compared with the simple graphene oxide decorated sensor. The covalent Ag-S links, in between the imprinted film and the silver nanocube decorated screen-printed carbon electrode, were crucial for imparting higher stability to the coating of the film. A perfect linearity in the current-concentration profile was observed, in the range 1.09-144.21 ng mL-1, with the detection limits of 0.16 (aqueous), 0.24 (blood plasma), 0.31 (pharmaceutics), and 0.42 (urine) ng mL-1 (S/N = 3). The proposed sensor was found to be useful in aqueous and real samples (human blood plasma, human urine, and pharmaceutics), without any matrix effect, cross-reactivity, or false-positives. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.
A reduced graphene oxide ceramic electrode modified with one MoNomer doubly imprinted acryloylated tetraamine cobalt phthalocyanine polymer for the simultaneous analysis of anticancerous drugs
(Elsevier B.V., 2019) Sana Fatma; Bhim Bali Prasad; Kislay Singh; Richa Singh; Swadha Jaiswal
The present work illustrates a novel technique for the development of One MoNomer dual imprinted polymer, utilizing acryloylated tetraamine cobalt phthalocyanine as a tetrafunctional monomer, on the surface of a reduced graphene oxide ceramic electrode. This electrode was used for the simultaneous analysis of a mixture of anticancerous drugs, chlorambucil and dacarbazine, at ultra-trace level in real samples. The acryloylated tetraamine cobalt phthalocyanine was typically selected in this work for polymerization because it served both as a monomer and a crosslinker, with higher electroconductivity. The detection sensitivity of the measurement was realized to be 0.041 ng mL−1 and 0.017 ng mL−1 for chlorambucil and dacarbazine, respectively in the aqueous environment. The complex matrices of blood plasma, urine and pharmaceutics were examined which yielded the validated results without any effects of matrix complications including cross-reactivity, and false-positives. The therapeutic ranges of the test analyte(s) (chlorambucil 0.159–28.524 ng mL−1, dacarbazine 0.063–37.286 ng mL−1) were realized to be larger demonstrating perfect linearity (R2 = 0.99) with the improved voltammetric response. This work merits special significance to decide the adequate supplementation of drug(s) in combined therapy for cancer treatment. © 2018 Elsevier B.V.
An AlgaSORB column for the quantitative sorption of arsenic(III) from water samples
(Canadian Association on Water Quality, 2006) Bhim Bali Prasad; Souri Banerjee; Dhana Lakshmi
This study examines a new Scytonema-based biosorbent (AlgaSORB-scy) using column chromatography for the biosorption of total inorganic arsenic [As(III) and As(V)] from aquatic samples. The AlgaSORB-scy was prepared by immobilizing a cyanobacterial biofilm (Scytonema-dimethyl-formamide slurry) over a polymer-modified silica gel and then characterized for stability and sorption/elution conditions under dynamic equilibrations followed by differential pulse polarographic detection. The sorbent exhibited a 100% affinity for As(III) in a multi-elemental solution [in the absence of As(V)] at pH 6.9 and a flow rate of 1 mL min-1 giving rise to a preconcentration factor as high as 44-fold. The interference caused by As(V) in the sorption of As(III) on AlgaSORB-scy necessitated the pre-reduction of As(V) into As(III) by sodium sulfite. The biosorbent was found to be suitable for total arsenic enrichment in the form of As(III) species and demonstrated a better endurance with a recyclability of up to 59 cycles of sorption-elution. The polymeric spacer between the cyanobacterial biofilm and the silica gel enabled the biofilm monolayer to be held firmly onto a solid support and be accessible for quantitative arsenic uptake without encountering any problems of interfacial overlapping, re-adsorption, or matrix effects in the drinking water supplied. Copyright © 2006, CAWQ.
An electroconducting copper (II) imprinted sensor using algae as cheap substitute of multiwalled carbon nanotubes
(Elsevier Ltd, 2016) Bhim Bali Prasad; Kislay Singh
A typical, reproducible, and rugged "complex-template" imprinted polymer-based pencil graphite electrode was fabricated for differential pulse anodic stripping voltammetric analysis of copper (II) (limit of detection, 0.004 ng mL-1, S/N = 3) in real-world samples. In this work, copper (II) ion mediated imprinting in alga (Aulosira sp.)-based molecularly imprinted polymer actually helped upbringing electro-conducting characteristics in the film. The modified electrode quantitatively responded copper (II), without any cross-reactivity and false-positives. Herein, encapsulated algal stains extended their carboxylate groups to imprint copper (II) in cooperation with an assistant monomer, N-methacryloylglutamic acid. The imprinted system simultaneously restricted the metal biosorption (non-specific adsorption) in acidic medium. The most interesting feature of algal stains was their ability to serve as an in-expensive alternative to the costly multi-walled carbon nanotubes. The results obtained by the proposed sensor could be utilized for the assessment of Cu (II) supplementation in metal-deficient patients and to estimate endogenous concentrations of Cu (II) in environmental, biological, and pharmaceutical samples. © 2015 Elsevier Ltd. All rights reserved.
An insulin monitoring device based on hyphenation between molecularly imprinted micro-solid phase extraction and complementary molecularly imprinted polymer-sensor
(2014) Mahavir Prasad Tiwari; Bhim Bali Prasad
Molecularly imprinted micro-solid phase extraction fiber was developed by modifying molecularly imprinted polymer film on the surface of silica fiber exploring "grafting via surface attached monomer" (method I) and "grafting via sol-gel" (method II) approaches. The latter approach was found to be inferior to the former one in terms of the sensitivity of insulin detection [method I, LOD=0.009ngmL-1; method II, LOD=0.064ngmL-1, RSD=1.21%]. Notably, either of the techniques, molecularly imprinted micro-solid phase extraction or complementary sensor, was found to be incompetent to monitor the stringent level of insulin in the real samples. However, the combination of these techniques has been found quite suitable for achieving the high detection sensitivity of ultra-trace insulin in human blood serum and Huminsulin injection, without any non-specific (false-positives) contributions. The proposed hyphenated device could serve as a possible marker for risk of developing type 2 diabetes mellitus and diabetic coma due to insulin resistance in human beings. © 2014 Elsevier B.V.
Application of polymer-modified hanging mercury drop electrode in the indirect determination of certain β-lactam antibiotics by differential pulse, ion-exchange voltammetry
(Wiley-VCH Verlag, 2003) Bhim Bali Prasad; Bhavana Arora
A selective and sensitive polymer-modified electrode was developed for β-lactam antibiotics (cefaclor, amoxycillin and ampicillin) present in formulated and blood plasma samples for the quantitative analysis in aqueous environment. The detection was made using an ion-exchange voltammetric technique, in differential pulse mode, on poly(N-chloranil N,N,N′,N′ -tetramethylethylene diammonium dichloride)-modified hanging mercury drop electrode of a three-electrode system (PAR Model 303A) attached with a Polarographic Analyzer/Stripping Voltammeter (PAR Model 264A). Antibiotics, which are electroinactive compounds, were essentially converted to their electroactive oxazolone analogues through acid treatment under drastic conditions (0.1 mol L-1 HCl, ∼85 °C, 2 h). These analytes in the form of their respective oxazolones were indirectly analyzed by oxazolone entrapment in the polymeric film through ion-exchange process at modified electrode surface (accumulation potential -0.20 V (vs. Ag/AgCl), accumulation time 120 s, pH 7.4, KH2PO4-NaOH buffer (ionic strength 0. 1 mol L-1), scan rate 10 mV s-1, pulse amplitude 25 mV). The limit of detection of cefaclor-derived oxazolone was found to be 2.12 nmol L-1 (0.82 ppb, S/N 3, RSD 3.21%) in terms of cefaclor (a representative β-lactam) concentration.
Ascorbic acid imprinted polymer-modified graphite electrode: A diagnostic sensor for hypovitaminosis C at ultra trace ascorbic acid level
(2011) Bhim Bali Prasad; Deepak Kumar; Rashmi Madhuri; Mahavir Prasad Tiwari
A new kind of molecularly imprinted polymer-modified graphite electrode was fabricated by "grafting-to" approach, incorporating sol-gel technique, for the detection of acute deficiency in serum ascorbic acid level (SAAL), manifesting hypovitaminosis C. The modified electrode exhibited ascorbic acid (AA) oxidation at less positive potential (0.0 V) than the earlier reported methods, resulting in a limit of detection as low as 6.13 ng mL -1 (RSD = 1.2%, S/N = 3). The diffusion coefficient (1.096 × 10-5 cm2 s-1), rate constant (7.308 s -1), and Gibb's free energy change (-12.59 kJ mol-1) due to analyte adsorption, were also calculated to explore the kinetics of AA oxidation. The proposed sensor was found to enhance sensitivity substantially so as to detect ultra trace level of AA in the presence of other biologically important compounds (dopamine, uric acid, etc.), without any cross interference and matrix complications from biological fluids and pharmaceutical samples. © 2011 Elsevier B.V. All rights reserved.
Barbituric acid sensor based on molecularly imprinted polymer-modified hanging mercury drop electrode
(Wiley-VCH Verlag, 2005) Bhim Bali Prasad; Dhana Lakshmi
A barbituric acid sensor based on molecularly imprinted polymer-modified hanging mercury drop electrode is reported for sensitive and selective analysis in aqueous and blood plasma samples. It was developed by coating directly the barbituric acid- imprinted polymer, which is prepared from melamine and chloranil, onto the surface of a hanging mercury drop electrode under charge-transfer interaction at +0.3 V (vs. Ag/AgCl) in Model 303A electrode system connected with a polarographic analyzer/stripping voltammeter (PAR Model 264A). The binding event of barbituric acid was detected in the imprinted polymer layer through differential pulse, cathodic stripping voltammetric (DPCSV) signal at optimized operational conditions [accumulation potential +0.3 V (vs. Ag/AgCl), accumulation time 120 s, pH 7.0 (without supporting electrolyte), scan rate 10 mV s-1, pulse amplitude 25 mV]. The limit of detection for barbituric acid was found to be 0.54 ppm (RSD = 3.7%, S/N = 3). The detection was feasible without any problem of matrix effect or cross reactivity in the linearity range of concentration varying from 0.50 to 125.00 ppm of barbituric acid. © 2005 Wiley-VCH Verlag GmbH & Co. KGaA.
Biomimetic piezoelectric quartz sensor for folic acid based on a molecular imprinting technology
(2011) Rashmi Madhuri; Mahavir Prasad Tiwari; Deepak Kumar; Aparna Mukharji; Bhim Bali Prasad
A novel molecularly imprinted polymer (MIP)-modified quartz crystal microbalance (QCM) sensor with high selectivity has been developed for the determination of folic acid via activator generated-atom transfer radical polymerization (AGET-ATRP) technique. It requires an alkyl halide (R-X) as an initiator, a transition metal complex as a catalyst, and an amine as reducing agent. Herein, chlorosilane was used as initiator which was grafted onto the self assembled monolayer modified-quartz crystal surface followed by the addition of pre-polymer mixture which latter underwent thermal cross-linking resulting in MIP-modified QCM sensor. The linear working range (quantification) was found to be 0.6-26.0 μg L-1, with the detection limit as low as 0.08 μg L-1 (S/N=3). ©2011 VBRI press.
Biomimetic Polymer-Based Electrochemical Sensor Using Methyl Blue-Adsorbed Reduced Graphene Oxide and Functionalized Multiwalled Carbon Nanotubes for Trace Sensing of Cyanocobalamin
(American Chemical Society, 2018) Richa Singh; Swadha Jaiswal; Kislay Singh; Sana Fatma; Bhim Bali Prasad
The paper reports a three-dimensional cyanocobalamin (Cbl)-selective biomimetic imprinted polymer. For this, a methyl blue-adsorbed reduced graphene oxide (rGO) and functionalized multiwalled carbon nanotubes (f-MWCNTs) composite, duly functionalized with acryloylurea, was used. This exhibited higher electroconductivity and larger surface area in comparison to either pristine carbon nanotubes or graphene. It is the first synthetic biomimetic polymer of Cbl, grown on the surface of a pencil graphite electrode. In this work, the adsorption of methyl blue over the rGO sheets improved its solubility, conductivity, and self-assembly properties. Such assemblies of rGO sheets and f-MWCNTs provide enhanced kinetics and conductivity to the entire architectural design of a molecularly imprinted polymer. The ultratrace detection of Cbl was feasible by differential-pulse voltammetric transduction. This sensor exhibited high sensibility and selectivity for Cbl detection, especially in real samples. © 2018 American Chemical Society.
Biosorptive separation of 'labile' fractions of copper and lead from river sediments and evaluation by differential pulse, anodic stripping voltammetry
(Inderscience Publishers, 2006) Bhim Bali Prasad; Rachana Singh; Dhana Lakshmi
The 'labile' copper and lead metal contents of contaminated sediments were extracted in different chemical solutions and then subjected for biosorptive separations. The sorbents called 'AlgaSORB-sp' and 'AlgaSORB-ch' were derived from two different algae, viz., Spirogyra and Chlorella, respectively. The metal detection was made by differential pulse, anodic stripping voltammetry. The retention of 'labile' species onto biosorbents in dynamic mode at optimised conditions of pH 6.9 and flow rate 1.0 mL/min in AlgaSORB-sp (copper ion) and AlgaSORB-ch (lead ion) led metal fractionations into labile and strongly complexed forms, in realistic terms. Copyright © 2006 Inderscience Enterprises Ltd.
Creatinine sensor based on a molecularly imprinted polymer-modified hanging mercury drop electrode
(Elsevier, 2006) Dhana Lakshmi; Bhim Bali Prasad; Piyush Sindhu Sharma
Molecularly imprinted polymers (MIP) have been elucidated to work as artificial receptors. In our present study, a MIP was applied as a molecular recognition element to a chemical sensor. We have constructed a creatinine sensor based on a MIP layer selective for creatinine and its differential pulse, cathodic stripping voltammetric detection (DPCSV) on a hanging mercury drop electrode (HMDE). The creatinine sensor was fabricated by the drop coating of dimethylformamide (DMF) solution of a creatinine-imprinted polymer onto the surface of HMDE. The modified-HMDE, preanodised in neutral medium at +0.4 V versus Ag/AgCl for 120 s, exhibited a marked enhancement in DPCSV current in comparison to the less anodised (≤+0.3 V) HMDE. The creatinine was preconcentrated and instantaneously oxidised in MIP layer giving DPCSV response in the concentration range of 0.0025-84.0 μg mL-1 [detection limit (3σ) 1.49 ng mL-1]. The sensor was found to be highly selective for creatinine without any response of interferents viz., NaCl, urea, creatine, glucose, phenylalanine, tyrosine, histidine and cytosine. The non-imprinted polymer-modified electrode did not show linear response to creatinine. The imprinting factor as high as 9.4 implies that the imprinted polymer exclusively acts as a recognition element of creatinine sensor. The proposed procedure can be used to determine creatinine in human blood serum without any preliminary treatment of the sample in an accurate, rapid and simple way. © 2006 Elsevier B.V. All rights reserved.
Determination of cefaclor by selective sample enrichment/clean-up on silica gel bonded polyelectrolyte in ion-exchange column chromatography
(2000) Sandeep Gupta; Bhim Bali Prasad
A silica gel-bound cationic polyelectrolyte, poly[N-chloranil N, N, N', N'- tetramethylethylene diammonium dichloride], modified as ion-exchanger capable of molecular recognition of β-lactam antibiotic, was used in solid phase extraction through column chromatography for a sample clean-up and enrichment of analyte from a dilute solution. The optimum and selective sorption conditions for a model antibiotic, cefaclor, were established. The high selectivity of polymer at pH 9.5 and flow rate as high as 5 ml/min were observed for the quantitative sorption of cefaclor. The desorption by 0.1 N HCl at flow rate of 0.1 ml/min and subsequent heating at 80°C for 2 h allowed the antibiotic to be detected as corresponding oxazolone form in UV-spectrophotometric and differential pulse adsorptive stripping voltammetric measurements. The potential of the suggested approach was illustrated by estimating cefaclor in urine and blood plasma samples. © 2000 Elsevier Science B.V.
Development of a creatinine sensor based on a molecularly imprinted polymer-modified sol-gel film on graphite electrode
(Wiley-VCH Verlag, 2008) Amit Kumar Patel; Piyush Sindhu Sharma; Bhim Bali Prasad
An electrochemical creatinine sensor based on a molecularly imprinted polymer (MIP)-modified sol-gel film on graphite electrode was developed. The surface coating of MIP over sol-gel was advantageous to obtain a porous film with outwardly exposed MIP cavities for unhindered selective rebinding of creatinine from aqueous and biological samples. A fast differential pulse, cathodic stripping voltammetric response of creatinine can be obtained after being preanodized the sensor in neutral medium containing appropriate amount of creatinine at +1.8 V versus SCE for 120 s. A linear response over creatinine concentration in the range of 1.23 to 100 mg mL-1 was exhibited with a detection limit of 0.37 mg mL-1 (S/N=3). © 2008 Wiley-VCH Verlag GmbH & Co. KGaA.
Development of highly electrocatalytic and electroconducting imprinted film using Ni nanomer for ultra-trace detection of thiamine
(Elsevier B.V., 2017) Bhim Bali Prasad; Richa Singh; Kislay Singh
The present work describes a new molecularly imprinted polymer-based electrochemical sensor for thiamine (vitamin B1), which has been fabricated exploiting both surface imprinting and nanotechnology. Of two monomers used in this work, N-methacryloylglutamic acid served as a biocompatible and bio-adhesive material, whereas the assistant monomer, acryloylated nickel nanoparticles-functionalized multiwalled carbon nanotubes (Ni nanomer) induced large electro-catalytic and conducting activities to the molecularly imprinted polymer film. The polymer synthesis was carried out, following the ‘surface grafting from’ protocol, with the free radical polymerization directly on the surface of Ni nanomer modified pencil graphite electrode. The presence of functionalized-MWCNTs in the polymer film was inevitable to render stability to the coating via aromatic π − π interactions at the film-nanomer modified electrode interface. Thiamine, being electrochemically inactive, was estimated indirectly by a probe, hexamine ruthenium (II) chloride, with signal transduction via differential pulse anodic stripping voltammetric technique. The limits of detection were in the range 0.17–0.2 ng mL−1(S/N = 3) in aqueous, multi-vitamin tablet, urine, and human blood serum, without any cross-reactivity and false- positives. The proposed sensor assures a reliable estimation of thiamine in the patients suffering from its acute deficiency. © 2017